Safety-fuse.



A. L. EUSTICE.

SAFETY FUSE. APPLICATION FILED MAR. 14.191

Patented Feb. 18,1919.

To all whom it mag concern:

UNITED sTATEs PATENT OFFICE. I

' ALFRED L. ElJ'ST-IIICE, OF CHICAGO, ILLINOIS, ASSIGNOR TO ECONOMY FUSE & MANUFAC- TURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK.

SAFETY-FUSE.

Specification of Letters Patent.

PatentedFeb. 18, 1919.

Be-it known that I, ALFRED L. EUs'rIoE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Safety-Fuses, of which the following is a specification.

My invention relates to safety fuses,- and refers particularly to inclosed fuses of the plug type. a

One of the objects of my present invention is to provide a plug fuse of inner and outer main members, upon the inner one of which the. fusible link may be properly mounted and secured independently of the outer member, andwhich members may be practically instantaneously separated for the purpose of examination of the fusible link wlthout disturbing the link-attaching means, and upon which said inner member a new fusible link may be quickly and easily mounted so that the fuse is capable of repeated use.

A further object of my invention consists in roviding adequate terminal connections upon the inner member for the ends of the fusible link so that there may be free passage of current through the link, and danger of arcing at the ends thereof is avoided.

A still further object of my invention consists in so disposing the fusible link connections that all danger of cross-arcing between opposite terminals 'of the fuse is avoided notwithstanding the location of the external contacts upon the respective inner and outer members both at the same end of the fuse, as is usual in plugfuses.

These and other advantages and objects of my invention will be more readily understood by reference to the accompanying drawings, which show a. preferred embodiment of my invention, and in .Which Figure 1 is a longitudinal section through the shell of my improved fuse, the removable portion ofthe fuse being shown in side elevation; v

F ig. 2 is a longitudinal section through the shell and removable portion of the fuse, this section being taken at an angle of ninety degrees to that of Fig. 1;

Fig. 3 is a sectional view taken on the line 33 of Fig. 1;

Fig. 4 is a sectional view taken on the line 44 of Fig. 2; and

Fig. 5 is a perspective of a portion of the fusible link.

, The outer main member comprises a hollow insulating shell 10 having an end portion 11 of restricted outside diameter, thread- .ed and receiving the ringterminal 12 with its inwardly-extending flange 13 which extends over the edge of the insulating shell,

as clearly shown in Figs. 1 and 2. The ring The terminal bolt 15 having the enlarged end contact 16 passes through a suitable aperture inthe cap 14. The endcap 14 is provided with the inwardly-extending boss- 17, and engaging the inner surface of the cap 14 is the terminal plate 18, of brass or other electrically conducting material. This terminal plate is preferably constructed with a peripheral portion 19 adapted to contact with the flange 13 of the terminal ring 11 and the link-receiving portions 20, with which the end of the fuse link is adapted to contact in a manner presently to be described. It will be observed that the inner ends of the link-receiving portions 20 engage opposite surfaces of the boss 17, so that rotation of the terminal late 18 is thereby prevented. 'The retaining ears 21 are formed at the inner ends of the link-receiving portions 20. The bent-over end 22 of the fusible link 23 is preferably provided with an aperture 24, through which the retaining ear 21 passes, thereby assisting in holding the end of the link in position.

The insulating post 25 is provided with a recess 26 at its end for the purpose of rethrough its entire length through which the thereby holding the insulating post 25 in posults, as the melting of the link is confined.

sition, while at the same time allowing the ready removal of the post with its associated parts.

The inner end of the terminal bolt 15 is threaded and receives the apertured terminal washers 32 of conducting material, these washers being held in position against the inner end of the insulating post 25 by means of the threaded nut 33, and receiving between them the bent-over end 34: of the link 23. It will now be observed that upon tightening of the nut 33 the terminal bolt 15 serves to rigidly clamp together the end cap 14, the terminal plate 18, and the insulating 0st 25, while at the same time the bent-over end 22 of the link 23 is brought into close contact with the link-receiving portion 20 of the terminal plate 18 by the end of the 1nsulating post 25, and the bent-over end 34.

of the link 23 is tightly clamped between the two terminal washers 32, thereby electrically connecting the link 23 with the terminal bolt 15 through the. nut 33. v

The fusible link 23 is preferably fiat and of zinc. Along its length it is provided with a plurality of portions 35 of restricted crosssectional area, between which are the portions 36 of substantially greater cross-sectional area. As set forth in Patent No. 1,217,289, granted to me on February 27', 1917 I have found that the use of sucha link in an inclosed fuse gives very superior re to the restricted portions 35, the portions 36 being separated from the rest of the link without melting.

Having described the various parts which are used in my invention, the operation of the same may now be readil understood: The various parts being assembled, as shown in Figs. 1 and 2, when the plug is screwed into a socket the end cap 14 is forced tightly against the shelland an excellent contact is obtained between the peripheral portion 19 of the terminal plate 18 and the inwardlyextending flange 13 of the terminal ring 12. When the plug fuse is thus in position the current passes through the terminal bolt 15, the nut 33 and the terminal Washers 32 to the link 23; through the link 23 to the terminal plate 18, and thence to the ring terminal 12, thereby completing the circuit through the fuse. the boss 17 effectually prevents all danger of cross-arcing of the current between the terminal bolt 15 and the terminal plate 18, while at the same time the insulating post It will be observed that 25 inclosing the terminal bolt 15 prevents all danger of cross-arcing between the terminal bolt and the fusible link 23.

In case of the rupture of the fusible link 23 under over-load or short-circuit conditions, the removable portion of the fuse consisting of the and cap 14, the terminal bolt 15, the insulating post 25, the link 23,.

and their associated parts, is withdrawn from the shell 10. The nut 33 is then loosened, allowing the bent-over end 34 of the link to be removed from between the terminal washers 32 and also allowing the insulating post 25 to be moved sufiiciently so that the bent-over end 22 may be disengaged if desired.

It will be 'evident that the link 23 may be applied to the removable portion of the fuse on either side inasmuch as two'link-receiving portions 20 of the terminal late 18 are provided and also two retaining ears 21, and that if desired two links may be simultaneously used on opposite sides of the fuse.

It will be evident to those skilled in the art that many changes .could be made in the detailed construction'of the parts which I have described without departing from the spirit and scope of my in the appended claims.

What I claim is:

" 1. In a' safety fuse, the combination of a hollow shell open at one end, a terminal ring on said shell, and a removable member adapted to said shell and comprising a cap of insulating material for the open end of said shell, electrically -conducting means carried bysaid cap and adapted to engage said terminal ring, a terminal bolt carried by invention, as defined said cap, means'wherebyi one end of a fusible link may be electrically connected with said conducting means and thereby "with said terminal ring,.and means whereby the other at one end with said terminal ring and said bolt carrying. means whereby the other end of said fusible link may be electrically connected with said terminal bolt.

3. In a safety fuse, the combination of an outer main member comprising a hollow shell open at one *end, a terminal ring on said shell and having an inwardly-extending flange atthe end of said shell, and an inner main member comprising a cap of insulating material for the open end of said shell, electrically conducting means carried by said cap and adapted to engage said flange, a terminal bolt carried by said cap, means carried by said cap and bolt whereby one end of a fusible link may be electrically- -connected at one end with said conducting means and thereb with said terminal ring and means where y the other end may be;

glectrically connected with said terminal olt. V p

4. In a safety fuse, the combination of an outer main member comprising a hollow shell open at one end, a terminal ring on said shell, and an inner readily separable main member comprising a cap of insulatmg. material for theopen end of said shell,

electrically conducting means carried by said cap and adapted to engage said terminal ring, a terminal bolt carried by said cap, an insulating post inclosing said terminal bolt, and means whereby one end of a fusible link may be electrically connected at one end with said conducting means and thereby with said terminal ring and means whereby the other end may be electricallyconnected with said terminal bolt.

5. In a safety fuse, the combination of an outer main member comprising a hollow shell open at one end, a terminal ring on said shell, and an inner readily separable main member comprising an apertured cap of insulating material for the open end of said shell, a terminal bolt extending through the aperture of said cap, a removable insulatingpost inclosing said bolt, and means whereby a'fusi-ble link may be electrically connected at one end with said terminal bolt at the inner end of said post and at its other end with said terminal ring.

I '6. In a safety fuse, the combination of a hollow shell open at one end, a terminal ring on said shell, an apertured cap of insulating material for the open end of said shell, electrically conducting means carried by said cap and ada ted. to engage said terminal ring, a terminal bolt extending through the aperture of said cap, a removable insulating post inclosing said terminal bolt, 'a fusible link electrically connected at one end of said insulating post with said terminal. bolt and at the opposite end of said insulating post with said conducting means, and means for clamping said insulating post to said cap.

7. In a safety fuse, the combination of a hollow shell open atone end, a terminal ring on said shell, an apertured capof insulating material for the open end of said shell, a terminal plate on the inner surface of said cap and'adapted to engage said terminal ring, a terminal bolt extending through the aperture' of said cap, a removable insulating post surrounding said terminal bolt, and

a fusible link having one 'end electrically connected to said terminal bolt at the, inner end of the post and the other end electrically connected to said terminal plate.

8. In a safety-fuse, the combination of a hollow shell open at one end, a terminal ring on said shell, an apertured cap of insulating material for the open end of said-shell and having an apertured boss. on its inner surface, a terminal bolt extending through the apertures of said cap and its boss, a terminal 'plate on the inner surface of said cap and adapted to engage said terminal ring, a removable insulating post surroundingsaid terminal bolt and having a recess into which said boss extends, and a fusible link having one end electrically connected with said terminal bolt and the other end clamped between the end of said insulating post and said terminal plate.

9.- In a safety fuse, the combination of a hollow shell open at one end, a terminal ring on said shell, an apertured cap of insulating material for the open end of said shell, electrically conducting means carried by said cap and adapted .to engage said terminal ring, a terminal 'bolt'extending through the aperture of said cap, a fusible link, a re movable insulating post inclosing said terminal bolt and adapted to clamp one end of said link against saidconducting means, and fastening means on said terminal bolt "adapted to electrically connect the opposite lating post inclosing saidterminal bolt andhaving a longitudinal rib fitting in the groove of said shell, and a fusible link electrically connected at one end with said ter minal bolt and at the other end with said terminal ring.-

11. In a safety fuse, the combination of a hollow shell open at one end and having a longitudinal groove on its inner surface, a terminal ring on said shell,.an apertured cap ofinsulating material for the'opcn end of said shell, a terminal bolt extending through the aperture of said cap, an insulating post inclosing said terminal bolt and having a longitudinal rib fitting in the Elm groove of said shell, a fusible link electrically connected atone end with said terminal bolt and at the other end with said terminal ring, and friction means in the groove of said shell for engaging said rib.

taining ear thereon, a fusible link having at one end an aperture through which said retaining ear passes, an insulating post 1n-' closing said terminal bolt and clamping said end of said link against said terminal plate, and fastening means for connecting the opposite end of said link with said terminal :bolt and for holding said insulating post,

said bolt and said cap in clamped relation.

I 13. In a safety fuse, the combination .of a

hollow shell having an open endv and provided with a pair of oppositely-disposed longitudinal grooves on its inner surface, a ter-- minal ring carried by said shell, an' apertured cap of insulating material for closing the open end of said shell, an apertured insulating boss on the inner surface of said cap, a

terminal plate on the inner surface of said' cap, said plate having a peripheral portion adapted to engage said terminal ring and a link-receiving portion extending to said boss,

' a terminal bolt extending through the apertures of said capand said boss, a removable.

insulating post inclos-ing said terminal bolt and having recesses for the reception of said boss, a pair of longitudinal ribs on said post and fitting in the grooves of said shell, friction means between one of said grooves and its engaging I'll), a fusible llnk havlng an apertured end clamped to said link-receivingportion of said terminal plate by said insulating post, a retaining car on said linkreceiving portion and extending through the aperture of said link, and means for electrically connecting the opposite end of said link to said terminal bolt.

14. In a safety fuse, the combination of a hollow shell open at one end, a terminal ring carried by said shell, and a unitary structure bodily removable from said shell and comprising an apertured insulating cap for the open end of the shell, a terminal bolt extending through the aperture of said cap, insulating means inclosing said bolt, a terminal member carried by said cap and adapted to engage said-terminal ring, and a fusible link removably connected at one end with'said terminal bolt and at the other end with said terminal member.

15. In a safety fuse, the combination ofv a hollow shell, a terminal ring on said shell, and a unitary structure removable from said shell and comprising a cap of insulating material to close the end of said shell, atermi nal'bolt carried by said cap, an insulating post inclosing said terminal bolt, a terminal.

plate carried by said cap and having a plu-.

rality oflink-receiving portions, said termi:

nal plate adapted to engage said terminal ring, and means for electrically connecting a phlirality of fusible links with said terminal 16; An electricalv safety fuse 'of the plug linkand electrically insulating means for spacing apart said attaching means, and whereby the-link is mounted independently of the outer main member and rendered removable therefrom without disturbing its attaching connections; the removable inner member carrying, means whereby the attachment for one end of the link is electrically connected with the external contact of the outer member by the act of inserting the inner member within the outer member.

17. An electrical safety fu'se of the plug type comprising inner and outer readily separable memberscarrying at or near. one end of the fuse the respective external contacts bywhich the fuse is introduced into the cirv cuit to be protected; the inner main member carrying electrically conductive means for attaching the respectiveends of a fusible link'and electrically insulating means for spacing apart said attaching means, and whereby the link is mounted independently of the outer main member and rendered rcmovable therefrom without disturbing its attaching connections; the removable inner member carrying means whereby the attachment for one end of the link is electrically connected with'the external contact of the outer member by the act of inserting the inner member within the outer member; the external contact of the outer main member comprising a securing thread by-which to secure the fuse in a socket, and its contact with said attachment for the link on the inner member being enforced by screwing the fuse into the socket.

18. An electrical vsafety fuse of the plug type comprising inner and outer readily separable members carrying at or near one end of the fuse the respective external contacts by which the fuse is introduced into the circuit to be protected; the inner main member carrying electrically conductive means for attaching the respective ends of a fusible link and electrically insulating means for spacing apart said attaching means, and whereby the link is mounted independently of the outer main member and rendered removable therefrom without disturbing its outer member by the act of inserting the inner member within the outer member; the external contact on the 1nner maln member comprising a central button and the external contact on the outer main member being constructed With a screw thread by which the fuse is inserted intoa socket; and the pressure of the electrical connection between the inner and outer members being developed by the screw'thread and the pressure of said central button;

In witness whereof, 1 hereunto subscribe my name this 10th day of March, A.D., 1917.

ALFRED L. EUSTI'CE. 

